The goal of Project II is to study the pharmacokinetics, biodistribution, dosimetry, therapeutic efficacy and toxicity of I- 131-labeled monoclonal antibodies directed against B cell differentiation antigens in patients with refractory B cell lymphomas. Patients will be treated with I-131-conjugated antibody MB-1 based on our preliminary studies in a patient with small cleaved cell lymphoma. Subjects will be given escalating doses of I-131-MB-1 and radiation dosimetry will be assessed by serial gamma camera imaging. Therapeutic doses of radiolabled MB-1 will be administered to patients in whom favorable dosimetry is achieved. Patients experiencing significant myelosuppression will receive stored autologous marrow (depleted of lymphoma cells by monoclonal antibody plus complement treatment). Future studies will be done to optimize biodistribution of radioimmunoconjugates and may include testing perinfusion of unlabeled MB-1, use of antibody fragments, alternate infusion schedules, and alternative pan B antibodies. The results of this project using radiolabeled against normal B cell differentiation antigens will be compared with those of Project I, in which radiolabeled tumor-specific anti-idiotype antibodies will be used.